1. Field of the Invention
The present invention relates to a method of printing realized by a client computer and a printer over a network, and particularly to a printing method using a server computer that relays between the client computer and the printer.
2. Description of the Related Art
The Internet consists of network systems and various computers that are interconnected by the network systems. Computers that are interconnected by the Internet can exchange information by using various systems such as mail systems and WWW systems.
Since the Internet is an open network system, relay systems belonging to various organizations, etc., exist in the routes for connecting the computers that communicate with each other. Therefore, in general, the network communication over the Internet has security risks such as tapping (lost secrecy), falsification of data (incomplete data), and pretending to be another person (illegitimate user). And it is necessary to deal with such security-related problems. As one countermeasure, network communications using SSL (Secure Socket Layer) are now commonly conducted. The SSL, which is a protocol belonging to the session layer of the OSI reference model, provides the functions of communicating coded data, authenticating by server, and authenticating messages.
To realize a network communication using the SSL, both the client computer and the server computer must support the SSL functions. As far as Web systems are concerned, a typical client program (browser) includes such functions by default. On the other hand, as for the server computers, although a Web server program has such functions, to actually use those functions the Web server program must also incorporate a server certificate (digital certificate) that is acquired from a certificate authority.
To construct, on a network, a site (print site) that provides a service of printing data, etc., in response to a print request from a client computer, it is necessary to address the above-described security-related problems. In this case, the SSL enables a secure network communication service even if the Internet is used.
However, to actually operate the sites that enable network communications using the SSL, the management of a lot of such print sites on the network would be very cumbersome because each site must acquire its own digital certificate and incorporate the same. On the other hand, a client computer must also acquire and incorporate the digital certificates corresponding to respective sites to be used.
In view of the above, the first object of the present invention is to provide a scheme in which even in the case where a lot of print sites, are constructed on a network, each of which provides a printing service by secure network communication, the print sites can be managed easily, as well as to provide a system to implement such a scheme.
In implementing such scheme, if a print site that provides a printing service is located inside a firewall (F/W), the print site cannot receive a print request from an external client computer that is sent by a secure network communication. This is because firewalls deny outside-to-inside access though it permits inside-to-outside access.
In view of this, the second object of the invention is to provide a scheme that enables a printing service by receiving a print request that is sent by a secure network communication even in the case where the print site is located inside a firewall, as well as to provide a system to implement such scheme.